Ceramic turbine airfoils with cooled trailing edge blocks

Abstract

A gas turbine engine hollow turbine airfoil, such as a first stage vane of a high pressure turbine of a gas turbine engine includes an outer wall surrounding a hollow interior. The outer wall extends radially outwardly in a spanwise direction from an airfoil base to an airfoil tip and has chordwise spaced apart leading and trailing edges and widthwise spaced apart pressure and suction side portions extending chordwise between the leading edge and a trailing edge block which terminates at the trailing edge. A plurality of trailing edge cooling air ducts extend chordwise through the trailing edge block aftwardly from the hollow interior and a plurality of trailing edge film cooling holes extend from the ducts through the trailing edge block. The cooling air ducts are preferably centered near a neutral axis of chordwise and spanwise bending of the trailing edge block. The trailing edge cooling air ducts converge aftwardly from the hollow interior and preferably converge in width with a substantially constant spanwise height. The invention is particularly suitable for turbine airfoils and vanes made with a ceramic matrix composite material such as one having a SiC matrix and, more particularly, with an SiC—SiC ceramic matrix composite. The airfoil is disposed between radially inner and outer segmented platforms that are, in one embodiment, integrally formed of a ceramic matrix composite (CMC) preferably a SiC—SiC CMC.